A conventional hologram recording method is disclosed in Patent Document 1. In the method disclosed therein, a reference beam (baseline beam) is applied to a hologram recording medium from a predetermined oblique direction at the incident angle of 35 degrees whereas a recording beam (object beam) is applied from an opposite oblique direction with respect to the direction in which the reference beam is made oblique, at about 90 degrees. The reference beam has a beam intensity modulated by e.g. an ND (Neutral Density) filter. Specifically, in the conventional hologram recording method, since the recording beam is applied obliquely to the hologram recording medium, apodization is employed for uniformalizing the beam intensity distribution of the Gaussian-beam as the reference beam on the Fourier plane, whereby SN ratio is improved.
Patent Document 1: JP-A-2003-43904
However, in the beam intensity uniformalization by apodization, the beam transmissivity is reduced partially, which results in a large light loss and this low light utilization efficiency has been a disadvantage in comparison with the cases where apodization is not employed.